Do We Have a New Release of IPC-7351C? |
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Tom H
Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5741 |
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Posted: 30 Jul 2023 at 5:05pm |
The main reason why IPC-7352 replaced IPC-7351B is because 7352 includes Through-hole technology.
IPC-7351 was 100% Surface Mount. The 7352 Naming Convention was expanded to include additional information like Thermal Pad size and other missing package data. IPC-7352 is not a Standard. It's been downgraded to a guideline. The real "Standard" for solder joint goals is IPC J-STD-001 Requirements for Soldered Electrical and Electronic Assemblies and it covers both Surface Mount and Through-hole technology. |
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cgnd
Active User Joined: 24 Mar 2021 Status: Offline Points: 22 |
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Is IPC-7352 intended as the replacement for IPC-7351B? Or is IPC-7352 intended to be used with IPC-7351B? As someone who is not involved with the development of these standards, it's a bit confusing trying to understand exactly what the differences between these two are.
The reason why I'm asking is because some other IPC standards use a "series" naming convention (e.g. IPC-6010 series with 6011, 6012, etc), where new revisions of each document use A, B, C, instead of changing the base document number. However, in the case of IPC-7352, it seems like the revision naming went IPC-7351A -> IPC-7351B -> IPC-7352 for some reason. If IPC-7352 is intended to supersede IPC-7351B, does anybody know why they didn't just name it IPC-7351C for consistency? Is there a description posted anywhere that details the changes/additions in IPC-7352 vs. the existing IPC-7351B doc? I haven't purchased IPC-7352 yet, and I'm trying to understand what the new standard includes that caused it to change the base document number instead of just going to rev C.
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dramos
Advanced User Joined: 18 Feb 2021 Status: Offline Points: 63 |
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Dear Tom,
Thanks for the info. I checked it several times... they needed a lot of time to repare the printer, more than six months hahahaha. Regards, David
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Tom H
Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5741 |
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IPC-7352 was released today - https://shop.ipc.org/ipc-7352/ipc-7352-standard-only/Revision-0/english
$170 |
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Tom H
Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5741 |
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The IPC-7352 only adds the Terminal Length in Gull Wing leaded packages (not flat lead packages).
People ask me which Land Pattern Naming Convention is the best?
I say PCB Libraries naming convention. We thought of everything to remove duplication of footprint names. All IPC documents for PCB design have been downgraded from "Standards" to "Guidelines". About 50% of all PCB designers don't use IPC documents for PCB design. The other 50% use IPC documents as a guideline but eventually develop their own standards. IPC is slowly pulling away from PCB design and focusing on Assembly and Fabrication. IPC J-STD-001 is the leading standard for Assembly Acceptability. All footprints should be IPC J-STD-001 compliant. IPC pulled the CID and CID+ training courses. They do have courses on Fabrication and Assembly. Select any of the buttons and you will not find any PCB design certification. |
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dramos
Advanced User Joined: 18 Feb 2021 Status: Offline Points: 63 |
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Dear Tom,
Many thanks for your replies. Starting from the end. It has a lot of sense to work with a footprint in a "horizontal" way instead of "vertical" way. Perhaps in a new revision of the standard (in the next 15 years) it will be taken into account. About the naming convention, I found another difference comparing two footprints, the lead size is not defined. IPC-7352 : QFN50P500X400X80-28N PCB Libraries: QFN28P50_500X400X80L40X25N I think that it could be useful in some cases. It gives more info about how it is the component. The final pad length depends of the component's lead size. Regards, David
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Tom H
Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5741 |
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The IEC 61188-7 Zero Component Orientation standard just reset the Pin 1 location to Lower Left, just like it was for 18 years under the IPC-SM-782 standard.
The IPC-7351B Pin 1 orientation in the Upper Left was a last minute change that should have never been adopted. IEC did not agree with the 2005 release Zero Component Orientation introduced in IPC-7351 so in 2007 IEC released IEC 61188-7 to correct the Zero Component Orientation back to what is was in IPC-SM-782. The IPC 1-13 Land Pattern committee never got a chance to vote on or approve the new Zero Component Orientation in IPC-7351. It was just slipped in at the last minute. This was a huge mistake by the 1-13 Land Pattern Committee chairman to approve this change. All rectangular component packages should be rotated to make the long direction "Horizontal" for many reasons. Your computer screen is long in Horizontal. Paper sizes are long in Horizontal. Most PCB designs are long in horizontal. This was never discussed in the final meeting where all the rectangular footprints were changed to the length in the Vertical direction. |
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Tom H
Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5741 |
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In V23 Footprint Expert "Console Options" there is a dropdown menu for 3 naming conventions:
The PCB Libraries naming convention was originally voted on and approved for IPC-7351C. The biggest difference between PCB Libraries and IPC-7352 is the location of the Pin Qty. PCB Libraries (IPC-7351C) the pin qty is in the beginning of the footprint name after the component family. IPC-7352 the pin qty is at the end of the footprint name (just like IPC-7351B). |
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dramos
Advanced User Joined: 18 Feb 2021 Status: Offline Points: 63 |
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Dear Tom and Team,
Firstly, Happy New Year! All the best for the new 2023. I have just installed the new version of Footprint Expert. I realized that the naming convention is quite similar to the defined in IPC-7351B. I need to read the new IPC-7352 to find the differences with the old IPC-7351B about the naming convention but could you advance something about it? Where was the issue to use the proposed naming convention by Footprint Library Expert? what about the zero component orientation position? is it according IPC-7351B or IEC 61188-7? Regards, David
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Tom H
Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5741 |
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The IPC-7352.opt file was missing from one of our program installers.
That was fixed and all versions now have that Option file. Footprint Expert will still follow the IPC-7351 mathematical model until if and when the industry accepts IPC-7352, which may take a year or so. But at least we have a workaround in the meantime. It's important to note that when you open the IPC-7352.opt file to immediately save as another name because the Enterprise will overwrite the IPC-7352.opt file with every update. V23.01 will be released the first week of January 2023 and it will support the new IPC-7352 Footprint Naming Convention in the Console Options. |
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